Inside St. Patrick’s Cathedral in Dublin, Ireland, there’s a door that tells a five-century-old tale. In 1492 two families, the Butlers and the FitzGeralds, began fighting over a high-level position in the region. The fight escalated, and the Butlers took refuge in the cathedral. When the FitzGeralds came to ask for a truce, the Butlers were afraid to open the door...